Category Archives: Effect of orography on Catalina

The models are showing a lot of rain ahead over the next two weeks–see farther down. In the meantime, this:

6:44 AM: back side of last rain blob passing over Catalina now. That should be it for today and the next several days.

It was STILL raining when I got up at 3:40 AM, another few minutes of rain in a never-ending series of brief light rains over the past 24 h. The total now over the past 72 h is no less than 1.34 inches here in Catalina! Wow.

And yesterday, with its persistent overcast, dark, dull, spritzed-with-mist periods of rain (approaching the official “drizzle” precipitation category), was, with its high temperature of only 53 F, as close to am early spring day in Seattle in Catalina as you could experience.

Here are some shots of that overcast with Stratocumulus day with exceptionally long captions as well, a style I seem to have “pioneered”:

10:20 AM. “Catalina Heights” in the foreground, and the Catalina Mountains topped with snow and orographic Stratocumulus as seen from Shroeder Street, a street BADLY in need of re-paving but our priorities are so SKEWED, we think building three sound walls along Oracle in the near future is more important in this time of austerity!Sorry, got worked up here over our 3rd World streets in Catalina, in which it is deemed a “fix” of a pothole by dumping a loose clump of asphalt in it. Still upset, too, over the blockage of the CDO wash by sound wall on Oracle. Outrageous since there are no homes behind that section of the wall and beyond.1:14 PM. Another area of light rain invades Oro Valley from the Tortolita Mountains to the west. This rain, having no strong shafting, tells you that the tops were humping up like rolling hills rather than are like towers. In humping up, they have gotten cold enough to have ice form in them whereas the other areas of Stratocumulus with no precip tells you they are too warm at top to form ice. SO Seattle-like here! TUS sounding yesterday afternoon indicated main tops at -10C (marginal for ice here) but likely humped tops to -12 C to -15 C, where ice can readily form.)5:06 PM. Slight color under mainly non-preciping Stratocumulus. Oddity here is that orange, sunlit haze on the left of Twin Peaks. Seemed to be moving right to left almost like a dust episode.

And this last rain episode, not even lasting 10 min, has plumped up the rain total for the past 24 h to 0.39 inches here in Catalina at 6:45 AM, ABOVE that amount that it was deemed there was only a ten percent chance of exceeding, 0.25 inches when writing yesterday. So even as much of a precipophile as I am, I could NEVER have foreseen so much here as in the past 24 h!

So, this morning, I am humbled, but feeling great that so much more rain fell in our droughty nearby desert.

Two sites in the Catalinas have received another 0.87 inches as of 5 AM AST, 0.75 inches in the past 6 h! View 24 h totals here, though being a rolling archive, unless you go right away you’ll see slightly different totals than I mention here.

This last 24 h of our rainy spell, too, is a good example of how Catalinans get more rain than in town WHEN the flow turns from almost due south as it was on Friday, to more from the southwest and west as has been the case yesterday and continuing into this morning. When the flow is more westerly, air piles up against the Catalinas AND over us deepening the clouds, ones that begin thickening well upwind, say around I-10 to the west, and then they often start preciping soon after they thicken up as the tops of the clouds get colder and reach the ice-forming level. When the flow is from due south, we are “shadowed” by Pusch Ridge and other portions of the Catalinas to the S, and our rain can be less than Tucson and the north metro area next to the Cat Mountains.

Most of our rain advantage over Tucson (17 inches vs. 12 inches) comes from the kind of days we had yesterday and early today.

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What can we learn from these past 72 hours?

When you’re in a “trough bowl”, as we are now , good things happen; storms often turn out to be better than you imagine, being all they can be, no duds.

“Nice” days now will only be temporary breaks while we’re in the trough bowl, the collecting zone for storms. As an exciting example of how the weather is in a trough bowl, there were TEN model output panels from last night’s run showing rain for SE AZ! It can hardly be better than that! Here are a couple of early panels with rain:

The 6 h ending at 11 AM today (unbelievable to me that its STILL raining in the mod then! Its like the “Miracle in Albuquerque” yesterday when the AZCats beat Neveda but had to score two TDs in the last 90 seconds to do it, doesn’t seem possible, will turn off TEEVEE and go do something else (as a friend really did. But there it is, its still raining here this morning, and a there WAS a miraculous win:Valid for Wednesday morning at 5 AM AST. This is the rain accumulation in the prior 6 h indicated by the area of green.Valid at 5 PM AST, Christmas Day. This follows a short break of several days, a break in which people get lulled into thinking its the end of the rainy spell, but they would be so WRONG! The rain shown here (green areas) is that rain the model believes has fallen in the prior 12 h (the period of rain lowers in resolution as the model gets farther away from its starting point; 6 h has become 12 h of rain areas.)

Go here to see them all, from IPS MeteoStar again. Too many rain panels; too little space. Quite the Big Bopper at the end of the run, too, on New Year’s Eve! One now wonders if after all the drought we’ve had, the sunny, comfy days, we’ll hear, after the next two to three weeks go by, complaints about how wet and cold its been? Humans: we’re like that. Me, too. I like complaining, especially about sound walls.

In sum, we are in a “bowl game”, a “trough bowl” where storms will be collecting off and on for the foreseeable future.

Be ready! It is the author’s experience that in some cases like this, the storms over a period of weeks, intensity, kind of go through a crescendo of sorts before the pattern changes back to dry again. Hope so. This would be great as an AZ drought buster.